Central retinal vein occlusion is a common vascular cause of blidness. In this paper, we first report focal haemorrhagic pigment epithelium detachment and chorioretinal anastomosis in the peripapillary area as an intraoperative complication of radial optic neurotomy (RON). A 65-year-old white man presented with ischaemic central vein occlusion OS. He underwent vitrectomy with RON, panretinal photocoagulation and intravitreal injection of triamcinolone acetonide. A circumscribed subretinal haemorrhage was noted intraoperatively at the nasal site of the RON. The haemorrhage size decreased at the seventh postoperative day when an optical coherence tomography scan disclosed a haemorrhagic pigment epithelium detachment. Fluorescein angiography and fundus photograph revealed a chorioretinal anastomosis formation nasal to the optic nerve confirmed by indocyanine green angiography. Best-correlated visual acuity improved from hand movements to 6/18 at the fourth week and it was stable until last examination. This case illustrates the role of chorioretinal anastomosis formation in the vision improvement following RON.